Normal vs. reverse fault – the example of curvature's usage on gravimetric data

The gravitational effects caused by normal and reverse faults are very close to each other, both in amplitude and in the shape. We demonstrate the usage of the first curvature as a tool for the setting the slope orientation without the additional geological information. The curvature is calculated not only for the measured data, but for their upward continuation, too. This step helps to lower instability of the curvature computation and is important in the interpretation of the resultant curvature as well. We applied this method on the synthetic test and on the real regional gravimetric data as well. The results show the method could be useful step before the density modelling process and generally during qualitative interpretation in applied gravimetry.

Ecological Influences on Tuber Aestivum Distribution in the Subcarpathian Region of Transylvania

The aim of this research was to identify the ecological factors which have influences on distribution, development and habitat suitability of the summer truffle (Tuber aestivum) in the Sub-Carpathian region of Transylvania. The ecological factors such as average annual temperature (°C), average annual precipitation (mm/year), the length of the bioactive period (months), land slope (grade), slope orientation, soil pH and its compaction level were analyzed having specific influences on forest vegetation development in Sub-Carpathian hills, and in the same time on the possibility of symbiosis existence between the trees and summer truffle. The most favorable regions from the Sub-Carpathians of Transylvania for summer truffle growth proved to be Dealurile Năsăudului and Homoroadelor Sub-Carpathians followed by Muscelele Năsăudului and hills of Bistrița, where the average annual temperature is between 6,8-11°C with an average annual precipitation of 900 mm/year, a 3-6 months long bioactive period and high humus content of the soil.

Variación arquitectónica y morfológica de Hintonia latiflora (Rubiaceae) en relación a la cosecha de corteza y factores ambientales

Hintonia latiflora is a rare ecologically and economically important species from the Tropical Deciduous Forest of the Balsas Basin, Mexico, whose bark is traded as medicinal. Debarking practices have modified the shape of plants, their architecture and morphometry; but it is unknown if some topographic and edaphic factors may also influence in these attributes. Here we propose that the ecological conditions of this species distribution and harvesting areas, may determine the morphometric characteristics and the individuals variation in their architecture. To test this hypothesis we assessed the relationship of topographic and edaphic factors on the morphological characteristics of saplings (n = 143) and adults (n = 117), in eight harvesting areas of H. latiflora. The harvesting areas, with a surface of 0.6 ha, were selected randomly with the support of participatory mapping elaborated by gatherers of the study site. Data were analyzed using principal components (PCA) and canonical correspondence (CCA) analyses. The first three PC explained 92.1 % of the morphological variation; height, basal diameter, and coverage, explained morphometric differences in both, saplings and adults, in all eight harvesting zones. The terrain slope, slope orientation, soil depth and stoniness, were ecological factors statistically related with morphometric differences. A lower terrain slope, little stoniness, soil depth, slope orientation E-W in saplings (azimuth 90˚-270˚) and N-S in adults (azimuth 0˚-180˚) were the factors associated to height, number of basal branches, basal diameter and coverage of H. latiflora. Areas with higher harvesting intensity were composed by monopodic trees and some reiterated basitone individuals; the adults of these areas also had more fruits. At these sites, plants of H.latiflora were more abundant and produced more bark, but the high-intensity of harvesting, changes plant architecture, forming shrubby, multi-stemmed individuals, that originally were mesotone trees. Areas with lower harvesting intensity were characterized by steep slopes, shallow and rocky soils, and were dominated by basitone trees of smaller size, thin and scarce in the area. These sites are the least recommended for harvesting, because they produce less bark per tree, and serve to preserve the species at the site. Based on these results, we can develop restoration programs in areas affected by commercial harvesting, establish forestry plantations in key sites to ensure the establishment and development of individuals with desirable characteristics for bark harvesting and contribute to in situ conservation of H. latiflora in the Alto Balsas Basin.

Seasonal, multi-scale spatial and slope-oriented effects in cambial dynamics: an evaluation of sampling methods in Cedrela odorata (Meliaceae) in an Atlantic Forest area

Studies of cambial dynamics have been employed to investigate the growth behavior of trees. In these investigations, however, spatial variation in cambial rhythm within the stem is usually not taken into account. This study aims to evaluate the contribution of multiple sampling scales on the cambial dynamics of Cedrela odorata L. (Meliaceae) in different seasons. The effects of slope orientation were also tested. Samples were processed and analyzed with standard plant histology techniques. Data from multiple sampling scales were analyzed with nested ANOVA for each season, and the total variance was partitioned according to the fraction related to each scale. The main sources of variability were associated with the scale of tree and scales smaller than 1 cm. Radial growth was not significantly related to acclivity orientation. Thus, to obtain samples that represent total variability in cambial dynamics, it is preferable to increase the number of sampled trees; to take multiple samples from a few millimetres apart from each other, or to assess multiple histological sections. Samples on scales greater than a few centimetres apart should not be given priority.